Confocal microscopy is an imaging technique that increases optical resolution and contrast using point illumination and pinholes to eliminate out-of-focus light in a specimen. FIG. 1A illustrates a convention confocal microscope 100. As illustrated, a sample 105 is illuminated using light source 110 through a pinhole 115. A lens 145 focuses illumination light 135 to a point on focal plane 150 passing through sample 105. Sample 105 is scanned in both lateral dimensions (X and Y) as well as the axial direction (Z), and the resulting image, acquired at camera 120 through pinhole 125, is a three-dimensional (“3D”) image. A beam splitter 130 is often used to pass the illumination light 135 to sample 105 while redirecting the reflected light 140 to camera 120. This type of sequential voxel-by-voxel scanning is slow and not suitable for large longitudinal studies and real time imaging. State-of-the-art confocal microscopes today use a spinning disk of pinholes, which increases throughput. However spinning disks are mechanically cumbersome and require a large form factor, limiting parallelization and scalability. If the throughput of confocal microscopy systems could increase by orders of magnitude, new paradigms in screening could be opened.
Confocal microscopy can be extended for use with fluorescence microscopes. A fluorescence microscope is a microscope that uses fluorescence or phosphorescence to image samples. FIG. 1B illustrates a conventional confocal fluorescence microscope 101 where a sample 155 is illuminated by an illumination source 160 through a pinhole 165. An excitation filter 170 limits the wavelength of the excitation light 175, which excites sample 155 to emit fluorescent light 180. The excitation light 175 is redirected by dichroic mirror 185 and focused onto focal plane 190 by objective lens 191. Fluorescent light 180 passes back through dichroic mirror 185, filtered by emission filter 192 to block undesirable wavelengths, and focused through pinhole 193 onto camera 194 by ocular lens 195. To achieve 3D images, sequential voxel-by-voxel scanning is used, which is slow and not suitable for longitudinal studies and real time imaging.